class Animal:
    def __init__(self, name):
        self.name = name

    def make_sound(self):
        pass


class Dog(Animal):
    def make_sound(self):
        print(self.name + " says woof!")


class Cat(Animal):
    def make_sound(self):
        print(self.name + " says meow!")


def animal_sound(animal):
    animal.make_sound()


dog = Dog("Buddy")
cat = Cat("Whiskers")

animal_sound(dog)
animal_sound(cat)
